Stock, I could see one easily getting 350-400K on it. I think that one person on the forum has seen a 7.3 pull into the shop for a transmission replacement at 600+K. Is the chip a mild one or aggressive?
2002 Ford F-350 7.3L Powerstroke 4x4 Supercab Automatic. Regularly grosses at 32,000lbs without breaking a sweat.

Replace the fuel pump about 220,000 (10 years old in my 2007)(will start leaking), replace the fuel filter assy. when it starts leaking (also will leak from corrosion ) (probably should have been drained more). Keep a cam position sensor in the glove box in case you ever need it. Get the Dealer fix on the cruise control sensor. Know a man with 604,000 miles on one. Probably ready to go through now but still a daily driver. Get the lifetime warranty starter where ever you buy it (first one lasted 160K...the replacements last about 45k each). Bought a new 2008 6.4 F-250 crewcab 2wd. Love the truck & power....hate the mileage (12.5 to 13.5 average mixed street & highway mileage .. mechanic said this was pretty good for a 6.4)(Old 7.3 crewcab with 5-speed and 4.10 gear got 17or 18 in town & 20 on the highway). Would buy a good used 2002 7.3 if I had it to do over again. (Only cost $51,000 to find that out)
Had a 7.3 got a 6.4 wish I had a 7.3 again!

i bought 2000 e350 7.3 new ,and i now have 249xxx miles no problems ,mild chip k&n airfilters way more power than i need just hauled bikes to sturgis ,hauls my boat veryrare to here trans kickdown on the highway ,35 gallon tank and i have hit 700 on trip several times driveing to florida 20 mpg at 75 mph 3.73 gears ,when i first bought it i planned on hittin 300xxx miles and junkin it ,now i am thinkin 500xxx its still like new towels on seats and thin carpet over original carpet always service fuel filter ,oil and filter at 5000mile flush trans every 60xxx ,very satisfied ford customer Dave Wirick 636-933-0855 crystal city mo

i bought 2000 e350 7.3 new ,and i now have 249xxx miles no problems ,mild chip k&n airfilters way more power than i need just hauled bikes to sturgis ,hauls my boat veryrare to here trans kickdown on the highway ,35 gallon tank and i have hit 700 on trip several times driveing to florida 20 mpg at 75 mph 3.73 gears ,when i first bought it i planned on hittin 300xxx miles and junkin it ,now i am thinkin 500xxx its still like new towels on seats and thin carpet over original carpet always service fuel filter ,oil and filter at 5000mile flush trans every 60xxx ,very satisfied ford customer Dave Wirick 636-933-0855 crystal city mo

i bought 2000 e350 7.3 new ,and i now have 249xxx miles no problems ,mild chip k&n airfilters way more power than i need just hauled bikes to sturgis ,hauls my boat veryrare to here trans kickdown on the highway ,35 gallon tank and i have hit 700 on trip several times driveing to florida 20 mpg at 75 mph 3.73 gears ,when i first bought it i planned on hittin 300xxx miles and junkin it ,now i am thinkin 500xxx its still like new towels on seats and thin carpet over original carpet always service fuel filter ,oil and filter at 5000mile flush trans every 60xxx ,very satisfied ford customer Dave Wirick 636-933-0855 crystal city mo